Magnetometer Harmonization Angle Estimation
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Solution Overview
Problem
Current methods for determining the magnetic heading of a mobile machine from Earth's magnetic field measurements are prone to angular errors due to misalignment of the magnetometer's coordinate system, requiring complex and time-consuming procedures for harmonization, especially on the ground.
Innovation Solution
A method to estimate horizontal harmonization angles (hx, hy) by calculating angles between the magnetometer's reference coordinate system and the aircraft's coordinate system using ellipse-defined angles from magnetic field vector measurements, allowing for ground-based compensation of magnetic flaws and improving in-flight accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heavy measurement procedures by optical sighting are used to determine harmonization defects, then measurement precision is improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The patent replaces complex optical sighting measurement procedures with a computational method using magnetic field vector measurements and mathematical calculations (ellipse fitting, angle estimation). The harmonization angles are determined through algorithmic processing of magnetometer data rather than manual optical measurement, significantly simplifying the procedure while maintaining accuracy
Solution Approach 2:
The system performs self-calibration by using its own magnetometer measurements to automatically compute harmonization defects. The mobile machine itself generates the measurement data needed to determine its own coordinate system misalignment, eliminating the need for external optical measurement equipment and procedures
2Measurement precision
If complete in-flight compensation procedures are used to identify harmonizations, then measurement precision is improved, but time consumption and operational constraints increase
Solution Approach 1:
The patent performs harmonization angle estimation during ground-based operations before flight. By determining the horizontal harmonization angles (hx, hy) using ellipse fitting from magnetic field measurements taken on the ground, the system prepares calibration data in advance, avoiding the need for time-consuming in-flight compensation procedures
Solution Approach 2:
The patent implements a partial compensation approach by focusing on determining only the horizontal harmonization angles (hx, hy) during ground operations, rather than performing complete in-flight compensation. This partial action suffices to significantly improve measurement accuracy without requiring full in-flight procedural execution
3Measurement precision
If magnetometer coordinate system is constrained to align with reference coordinate system, then measurement precision is improved, but ease of manufacture deteriorates due to heavy constraints
Solution Approach 1:
The patent transforms the problem from physical alignment constraint to computational parameter adjustment. Instead of requiring the magnetometer to be physically aligned with the reference coordinate system during installation, the system determines harmonization angles (hx, hy, hz) as computational parameters that correct for misalignment. This allows flexible installation while maintaining measurement precision through mathematical transformation of the coordinate systems
Data Source
AI summary
A method for estimating the harmonization values of a magnetometer installed in a mobile machine, said magnetometer being associated with its reference coordinate system XM, YM, ZM, said method, implemented by an electronic device, comprising acquiring magnetic field values measured by the magnetometer and determining the horizontal harmonization (hx, hy) by:estimating a first angle equal to the angle between XM and the large axis of an ellipse, defined in the plane comprising the two axes XM, ZM, by said acquired field values;determining hy as being equal to said first estimated angle,estimating a second angle equal to the angle between YM and the large axis of an ellipse defined, in the plane comprising the two axes YM, ZM, by said acquired field vector values; anddetermining—hx as being equal to said second estimated angle.